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| author | Daniel Santos <daniel.santos@pobox.com> | 2013-02-21 16:41:45 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-02-21 17:22:16 -0800 |
| commit | 1d6a0d19c85587581a364850b77f30446810a560 (patch) | |
| tree | f82e7ac260a7705459c77bd37bf2733047542921 /include/linux/bug.h | |
| parent | ca623c914e82c3351cd657073fdb24a1df8c27b9 (diff) | |
| download | lwn-1d6a0d19c85587581a364850b77f30446810a560.tar.gz lwn-1d6a0d19c85587581a364850b77f30446810a560.zip | |
bug.h: prevent double evaulation of `condition' in BUILD_BUG_ON
When calling BUILD_BUG_ON in an optimized build using gcc 4.3 and later,
the condition will be evaulated twice, possibily with side-effects. This
patch eliminates that error.
[akpm@linux-foundation.org: tweak code layout]
Signed-off-by: Daniel Santos <daniel.santos@pobox.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Joe Perches <joe@perches.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/bug.h')
| -rw-r--r-- | include/linux/bug.h | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/include/linux/bug.h b/include/linux/bug.h index 27d404f91b3e..89fb91d0c929 100644 --- a/include/linux/bug.h +++ b/include/linux/bug.h @@ -59,9 +59,10 @@ struct pt_regs; extern int __build_bug_on_failed; #define BUILD_BUG_ON(condition) \ do { \ - ((void)sizeof(char[1 - 2*!!(condition)])); \ - if (condition) __build_bug_on_failed = 1; \ - } while(0) + bool __cond = !!(condition); \ + ((void)sizeof(char[1 - 2 * __cond])); \ + if (__cond) __build_bug_on_failed = 1; \ + } while (0) #endif /** |